https://bugzilla.kernel.org/show_bug.cgi?id=220491 --- Comment #34 from Paul Ausbeck (paula@xxxxxxxxxxxxxxxxxxx) --- Alan: It may be that the usbmon trace associated with comment #9 is not what I thought it was. Since I can't readily interpret these traces I can't verify that they contain what I think they contain. I may have made a mistake. When I say that a device disconnects/reconnects I get this information from the dmesg log. I did my best to match the usbmon trace to a proper dmesg log but I may have made a mistake. I want to emphasize that every time the device disconnects/reconnects as far as the dmesg log is concerned, the USB filesystem is unmounted. Every time that the device merely resets and does not disconnect/reconnect the USB filesystem remains mounted. Here is a log snippet where the device, 3-4, disconnects/reconnects: [22784.760311] usb 3-4: USB disconnect, device number 3 [22784.761239] pci_bus 0000:01: Allocating resources [22784.761855] pci_bus 0000:01: Allocating resources [22784.762047] done. [22784.762056] random: crng reseeded on system resumption [22784.876977] PM: suspend exit [22784.878740] usb 2-4: new full-speed USB device number 15 using xhci_hcd [22785.031677] usb 2-4: New USB device found, idVendor=0cf3, idProduct=e300, bcdDevice= 0.01 [22785.031687] usb 2-4: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [22785.036360] usb 2-4: USB disconnect, device number 15 [22785.214926] usb 3-4: new SuperSpeed USB device number 4 using xhci_hcd Here is what a reset with no disconnect/reconnect looks like: [ 58.003736] usb 3-4: reset SuperSpeed USB device number 2 using xhci_hcd If the device is always disconnecting/reconnecting at the usbmon level, this is not always being propagated up to the usbcore level. To the extent that is true, the usb_persist mechanism is already working at least part of the time. If usb_persist is already working part of the time that should make it easier to get it to work all the time. Just to verify that I did not make a mistake on comment #9, I'll attach another usbmon trace where there is no disconnect/reconnect at the usbcore level. The trace that I'm attaching has Bi/Bo:3:002 in every line. I interpret this as meaning that the host is only talking to the USB storage device. When a disconnect/reconnect occurs I also see usbmon lines that contain Bi/Bo:3:001, which I interpret as talking to the associated hub, and Bi/Bo:3:003 which I interpret as talking to the reincarnated device through a new device ID. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
